1. Field of the Invention
The present invention relates to the field of tape drives for recording information, and more particularly, to arrangements and methods for driving the cartridge roller of a tape cartridge.
2. Description of Related Art
Tape drives for recording information, such as digital data, typically employ an electric motor and an arrangement for transferring the force of the motor to drive the cartridge roller of a tape cartridge. The cartridge roller moves a belt within the tape cartridge that advances the tape within the cartridge. The tape is moved past a read/write head arrangement that reads and writes data from and to the tape.
A top view of a conventional tape drive is depicted in FIG. 1. The tape drive 10 receives a tape cartridge 12 on which data is to be written or from which data is to be read. Upon full insertion of the tape cartridge 12 in to the tape drive 10, a cartridge roller 18 bears against an idler 16, and pushes the idler into driving contact with a motor 14. Insertion of the tape cartridge 12 opens a cartridge door 20, exposing an opening 22 by which the tape in the cartridge 12 passes. The read/write head 24 is positioned at the opening 22 for reading and writing the digital information.
The cartridge roller 18 is driven by rotation of the motor 14, via the idler 16, to advance the tape contained within the tape cartridge 12. An idler 16, or some other arrangement, is needed to transfer the motor force to the cartridge roller 18 since the motor 14 is too large to be brought to bear directly against the cartridge roller 18 because of the presence and location of read/write head 24 in relation to the cartridge roller 18.
A side view of the motor 14, idler 16, and tape cartridge 12 of FIG. 1 is depicted in FIG. 2A. Because of the indirect driving of the cartridge roller 18, this arrangement has a number of disadvantages, including the need for a number of additional elements, such as a driver 26 and bearings 28 for the idler 16. The driver 26 is coupled to the motor 14, and the idler 16 has an elastomeric coating 30. These elements add to the cost of the tape drive, result in lower performance due to loss of motion, and increase the size of the tape drive.
Different arrangements for driving the cartridge roller 18 of a tape cartridge 12 are depicted in FIGS. 2B and 2C. In FIG. 2B, the motor 34 rotates an attached pulley 36 that drives a belt 32. A second pulley 38 is driven by the belt 32. A capstan 40 is attached to the second pulley 38 and bearings 42 are provided. This arrangement suffers the same disadvantages as that of FIG. 2A, with the additional disadvantage of the need for belt replacement.
The arrangement of FIG. 2C overcomes the loss of motion in the other described arrangements by using a motor 44 with an extended shaft 46 and a capstan 48 at the end of the shaft 46. While this arrangement also reduces the number of elements and provides a direct drive of the cartridge roller 18, the extended shaft makes the arrangement excessively high, so that the size of the tape drive in the vertical direction would have to be increased to accommodate the arrangement. This runs counter to the current design philosophy in the computer industry to provide compact devices, rendering a tape drive employing this arrangement undesirable.